1. Field of the Invention
The present invention relates to a network transmission method, more particularly to a transcoding method for continuous video display regardless of bandwidth changes in a network.
2. Description of the Related Art
Real time broadcasts using an IP networks are commercially available.
When executing a conventional video data transmission, video/audio data should be transmitted in a compressed form because of large volume of data generally involved. Real time transmission characteristics are very important to various application services. Such application services include for example, a digital broadcast, a VoD (Video on Demand), video conferencing, and etc. The bandwidths of such application services can vary based on times of the services, especially in case of the best-effort scheme such as an Ethernet which generally does not have a fixed and unique bandwidth.
In the conventional video data transmission as mentioned above, losses and delays of the IP networks exert a detrimental influence on streaming services of multimedia data. Especially, the burst transmission characteristic of the IP network can severely hinder the QoS (Quality of Service) of multimedia data streaming services when providing the real time broadcast through the IP network.
For example, when a subscriber watches TV which receives a 20 Mbps HD broadcast signal of the highest QoS via a conventional network system, if the network system performance has deteriorated (due to a congestion of service requests from subscribers), the subscriber cannot continue to receive the HD broadcast service via the TV because there are no means for overcoming or curing properly the changed condition of video transmission operation.